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United States Patent | 5,546,458 |
Iwami | August 13, 1996 |
A handsfree communication apparatus utilizing a plurality of microphones to allow simultaneous communication by a plurality of persons. The plurality of microphones are separately provided apart from one another. An amplifier section (or a noise canceller) includes a plurality of operational amplifiers for signal amplification individually corresponding to the plurality of microphones, and differential amplifier circuit for executing a differential amplification. Through the differential amplification, simultaneously input noise components are canceled out and reduced, and at the same time speech components are extracted.
Inventors: | Iwami; Akiko (Amagasaki, JP) |
Assignee: | Mitsubishi Denki Kabushiki Kaisha (Tokyo, JP) |
Appl. No.: | 397835 |
Filed: | March 2, 1995 |
May 18, 1994[JP] | 6-104057 |
Current U.S. Class: | 379/392.01; 379/395; 379/419; 381/92; 381/94.7 |
Intern'l Class: | H04M 001/00 |
Field of Search: | 379/390,387,395,419,433,58,57 381/92,94 |
5379338 | Jan., 1995 | Umemoto et al. | 379/58. |
5381473 | Jan., 1995 | Andrea et al. | 379/395. |
5384843 | Jan., 1995 | Masuda et al. | 379/390. |
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